Image processing techniques for detecting objects in images can have many practical applications. For example, image processing techniques that detect a reference object in an image can be used to determine whether an image object representative of a particular product, a particular logo, a particular brand identifier, etc., is present as a product placement in a television broadcast, is present in a print or online advertisement, is present in an image depicting a store's inventory, etc. To be practical, such image processing techniques should be able to detect the reference object at an arbitrary location and with an arbitrary size in the image scene.